Search PubMed⌕ Search

Biomedical subjects

M A Ryan

Publications and source records attributed to M A Ryan.

At least 19 recordsLinked to original sources
PubMed2004

Polymer-carbon black composite sensors in an electronic nose for air-quality monitoring.

An electronic nose that uses an array of 32 polymer-carbon black composite sensors has been developed, trained, and tested. By selecting a variety of chemical functionalities in the polymers used to make sensors, it is possible to construct an array capable of identifying and quantifying a broad range of target compounds, such as alcohols and aromatics, and distinguishing isomers and enantiomers (mirror-image isomers). A model of the interaction between target molecules and the polymer-carbon black composite sensors is under development to aid in selecting the array members and to enable identification of compounds with responses not stored in the analysis library.

Air Conditioning↗
PubMed2003

A comparison of the metabolism of eighteen-carbon 13C-unsaturated fatty acids in healthy women.

Altered use of different dietary fatty acids may contribute to several chronic diseases, including obesity, noninsulin-dependent diabetes mellitus, and cardiovascular disease. However, few comparative data are available to support this link, so the goal of the present study was to compare the metabolism of [(13)C]oleate, [(13)C]alpha-linolenate, [(13)C]elaidate, and [(13)C]linoleate through oxidation and incorporation into plasma lipid fractions and adipose tissue. Each tracer was given as a single oral bolus to six healthy women. Samples were collected over 8 days, and (13)C was analyzed using isotope ratio mass spectrometry. At 9 h postdose, cumulative oxidation was similar for [(13)C]elaidate, [(13)C]oleate, and [(13)C]alpha-linolenate (19 +/- 1%, 20 +/- 4%, and 19 +/- 3% dose, respectively). Significantly lower oxidation of [(13)C]linoleate (12 +/- 4% dose; P < 0.05) was accompanied by its higher incorporation into plasma phospholipids and cholesteryl esters. Abdominal adipose tissue was enriched with [(13)C]alpha-linolenate, [(13)C]elaidate, or [(13)C]linoleate within 6 h. The percentage linoleate in plasma phospholipids correlated positively with [(13)C]linoleate and [(13)C]elaidate oxidation, indicating a potential role of background diet. Conversion of [(13)C]linoleate and [(13)C]alpha-linolenate to longer chain polyunsaturates was a quantitatively minor route of utilization.

Adipose Tissue↗
PubMed2003

Molecular modeling of polymer composite-analyte interactions in electronic nose sensors.

We report a molecular modeling study to investigate the polymer-carbon black (CB) composite-analyte interactions in resistive sensors. These sensors comprise the JPL electronic nose (ENose) sensing array developed for monitoring breathing air in human habitats. The polymer in the composite is modeled based on its stereoisomerism and sequence isomerism, while the CB is modeled as uncharged naphthalene rings with no hydrogens. The Dreiding 2.21 force field is used for the polymer, solvent molecules and graphite parameters are assigned to the carbon black atoms. A combination of molecular mechanics (MM) and molecular dynamics (NPT-MD and NVT-MD) techniques are used to obtain the equilibrium composite structure by inserting naphthalene rings in the polymer matrix. Polymers considered for this work include poly(4-vinylphenol), polyethylene oxide, and ethyl cellulose. Analytes studied are representative of both inorganic and organic compounds. The results are analyzed for the composite microstructure by calculating the radial distribution profiles as well as for the sensor response by predicting the interaction energies of the analytes with the composites.

Air Conditioning↗
PubMed2001

National Department of Defense Surveillance for Invasive Streptococcus pneumoniae: antibiotic resistance, serotype distribution, and arbitrarily primed polymerase chain reaction analyses.

To provide surveillance among US military personnel and their beneficiaries, 157 invasive Streptococcus pneumoniae clinical isolates were collected systematically from 7 large military hospitals between August 1997 and August 1999. The isolates were studied for antibiotic resistance, and 120 were serotyped and subjected to arbitrarily primed polymerase chain reaction (AP-PCR). Fifty (31.9%) of 157 isolates had intermediate or high-level resistance to penicillin, and 15.9% had multidrug resistance. The most common serotypes were 4, 6B, 9V, 14, 19F, and 23F. Those serotypes associated with penicillin resistance were 6B, 9V, 19A, and 19F. Most invasive disease cases were caused by serotypes included in the currently available 23- and 7-valent pneumococcal vaccines. By use of AP-PCR, 4 DNA groups were correlated with health care site (P< or =.0001). These results are valuable in assessing appropriate use of antibiotics and vaccines against S. pneumoniae in both military personnel and their families.

Adolescent↗
PubMed2001

The Department of Defense Birth Defects Registry: overview of a new surveillance system.

BACKGROUND: The U.S. Department of Defense (DoD) is challenged with monitoring and protecting the health and wellbeing of its service members. The growing number of women on active duty and the diverse hazardous exposures associated with military service make reproductive health issues a special concern of DoD. To address this concern, the DoD Birth Defects Registry was established at the DoD Center for Deployment Health Research located at the Naval Health Research Center, San Diego, California. METHODS: The registry captures comprehensive data on healthcare utilization to calculate the prevalence of birth defects in the children of military beneficiaries. Population-based electronic surveillance is supplemented by active case validation efforts. RESULTS: Since its establishment in 1998, the registry has captured data on more than 90,000 births that occur in military families each year. Detailed analyses, to include linking registry data with military occupational exposure data (e.g., anthrax vaccination), are underway. CONCLUSIONS: The DoD Birth Defects Registry provides important reproductive health information on the geographically dispersed military population. This program is expected to complement civilian public health programs and be especially valuable to military members and their families.

Congenital Abnormalities↗
PubMed2001

Lipid and fatty acid profiles in rats consuming different high-fat ketogenic diets.

High-fat ketogenic diets are used to treat intractable seizures in children, but little is known of the mechanism by which these diets work or whether fats rich in n-3 polyunsaturates might be beneficial. Tissue lipid and fatty acid profiles were determined in rats consuming very high fat (80 weight%), low-carbohydrate ketogenic diets containing either medium-chain triglyceride, flaxseed oil, butter, or an equal combination of these three fat sources. Ketogenic diets containing butter markedly raised liver triglyceride but had no effect on plasma cholesterol. Unlike the other fats, flaxseed oil in the ketogenic diet did not raise brain cholesterol. Brain total and free fatty acid profiles remained similar in all groups, but there was an increase in the proportion of arachidonate in brain total lipids in the medium-chain triglyceride group, while the two groups consuming flaxseed oil had significantly lower arachidonate in brain, liver, and plasma. The very high dietary intake of alpha-linolenate in the flaxseed group did not change docosahexaenoate levels in the brain. Our previous report based on these diets showed that although ketosis is higher in rats consuming a ketogenic diet based on medium-chain triglyceride oil, seizure resistance in the pentylenetetrazol model is not clearly related to the degree of ketosis achieved. In combination with our present data from the same seizure study, it appears that ketogenic diets with widely differing effects on tissue lipids and fatty acid profiles can confer a similar amount of seizure protection.

Animals↗
PubMed2001

Handwashing and respiratory illness among young adults in military training.

OBJECTIVES: In response to increasing concerns about respiratory illness in military recruits, a simple handwashing program was developed and evaluated at a large Navy training center. METHODS: Clinical records from 1996 through 1998 were reviewed to determine weekly rates of respiratory illness before and after program implementation (1,089,800 person-weeks reviewed). A supplemental survey was given to a sample of recruits to assess self-reported respiratory illness and compliance with the handwashing program. RESULTS: A 45% reduction in total outpatient visits for respiratory illness was observed after implementation of the handwashing program. No change was noted in hospitalization rates for respiratory illness, which remained low during the observation period. Survey data supported clinical observations, as frequent handwashers self-reported fewer respiratory illness episodes when compared to infrequent handwashers. Surveys also revealed challenges with handwashing compliance. CONCLUSIONS: Implementation of a handwashing program in this population of healthy young adults was associated with a marked reduction in outpatient visits for respiratory illness. Despite its success, maintenance of the handwashing program has been challenging in the time-constrained setting of military training.

Adult↗
PubMed2001

Low power, lightweight vapor sensing using arrays of conducting polymer composite chemically-sensitive resistors.

Arrays of broadly responsive vapor detectors can be used to detect, identify, and quantify vapors and vapor mixtures. One implementation of this strategy involves the use of arrays of chemically-sensitive resistors made from conducting polymer composites. Sorption of an analyte into the polymer composite detector leads to swelling of the film material. The swelling is in turn transduced into a change in electrical resistance because the detector films consist of polymers filled with conducting particles such as carbon black. The differential sorption, and thus differential swelling, of an analyte into each polymer composite in the array produces a unique pattern for each different analyte of interest, Pattern recognition algorithms are then used to analyze the multivariate data arising from the responses of such a detector array. Chiral detector films can provide differential detection of the presence of certain chiral organic vapor analytes. Aspects of the spaceflight qualification and deployment of such a detector array, along with its performance for certain analytes of interest in manned life support applications, are reviewed and summarized in this article.

Air Conditioning↗
PubMed2001

Timmy pats.

Explore the source record for details and available documents.

Anecdotes as Topic↗
PubMed2001

Pneumococcal vaccine to counter emerging infectious disease threat in the military.

Streptococcus pneumoniae causes severe morbidity and mortality worldwide and poses a significant threat to the health and readiness of U.S. military personnel. Although a vaccine to prevent pneumococcal infections has been available for almost 25 years, its use has been limited. Recently, increasing antibiotic resistance among S. pneumoniae strains has emerged, prompting health care professionals to reevaluate the benefit of administering pneumococcal vaccine. The Naval Health Research Center, in collaboration with professionals from numerous civilian and military organizations, has initiated a rigorous double-blind, placebo-controlled trial investigating the operational value of vaccinating young adults as they enlist in the military.

Humans↗
PubMed2000

Adult adenovirus infections: loss of orphaned vaccines precipitates military respiratory disease epidemics. For the Adenovirus Surveillance Group.

Adenovirus vaccines have greatly reduced military respiratory disease morbidity since the 1970s. However, in 1995, for economic reasons, the sole manufacturer of these vaccines ceased production. A population-based adenovirus surveillance was established among trainees with acute respiratory illness at 4 US military training centers as the last stores of vaccines were depleted. From October 1996 to June 1998, 1814 (53.1%) of 3413 throat cultures for symptomatic trainees (78% men) yielded adenovirus. Adenovirus types 4, 7, 3, and 21 accounted for 57%, 25%, 9%, and 7% of the isolates, respectively. Unvaccinated trainees were much more likely than vaccinated trainees to be positive for types 4 or 7 (odds ratio [OR] = 28.1; 95% CI, 20.2-39.2). Two training centers experienced epidemics of respiratory disease affecting thousands of trainees when vaccines were not available. Until a new manufacturer is identified, the loss of orphaned adenovirus vaccines will result in thousands of additional preventable adenovirus infections.

Adenovirus Infections, Human↗
PubMed2000

Sesquiterpene lactones are potent inhibitors of interleukin 8 gene expression in cultured human respiratory epithelium.

Sesquiterpene lactones, derived from Mexican-Indian medicinal plants, are known to have potent anti-inflammatory properties but the mechanisms of this effect are not completely understood. Recent data demonstrated that sesquiterpene lactones were potent inhibitors of the pro-inflammatory transcription factor NF-kappaB. Because activation of NF-kappaB is involved in the regulation of the chemokine interleukin 8 (IL-8), we hypothesized that the sesquiterpene lactones, isohelenin and parthenolide, would inhibit IL-8 gene expression in cultured human respiratory epithelium. Incubating A549 cells with tumour necrosis factor alpha (TNF-alpha) induced IL-8 mRNA expression and secretion of immunoreactive IL-8. Pretreatment with either isohelenin or parthenolide inhibited TNF-alpha-mediated IL-8 gene expression in a concentration-dependent manner. Pretreatment with either compound inhibited TNF-alpha mediated activation of the IL-8 promoter and TNF-alpha-mediated nuclear translocation of NF-kappaB. In addition, pretreatment with isohelenin or parthenolide inhibited TNF-alpha-mediated degradation of the NF-kappaB inhibitory protein, I-kappaBalpha. We conclude that sesquiterpene lactones are potent in vitro inhibitors of IL-8 gene expression in cultured human respiratory epithelium. The most proximal mechanism of inhibition appears to involve inhibition of I-kappaBalpha degradation. Stabilization of cytoplasmic I-kappaBalpha leads to inhibition of NF-kappaB nuclear translocation and of subsequent IL-8 promoter activation. The ability of sesquiterpene lactones to modulate IL-8 gene expression may explain, in part, their anti-inflammatory effects.

Anti-Inflammatory Agents↗
PubMed2000

The effect on serum lipids and oxidized low-density lipoprotein of supplementing self-selected low-fat diets with soluble-fiber, soy, and vegetable protein foods.

An increased intake of soluble fiber and soy protein may improve the blood lipid profile. To assess any additional benefit on serum lipids of providing soy protein and soluble-fiber foods to hyperlipidemic subjects already consuming low-fat, low-cholesterol therapeutic diets, 20 hyperlipidemic men and postmenopausal women completed 8-week test and control dietary treatments in a randomized crossover design as part of an ad libitum National Cholesterol Education Program (NCEP) step 2 therapeutic diet (<7% saturated fat and <200 mg/d cholesterol). During the test phase, foods high in soy, other vegetable proteins, and soluble fiber were provided. During the control phase, low-fat dairy and low-soluble-fiber foods were provided. Fasting blood lipid and apolipoprotein levels were measured at 4 and 8 weeks of each phase. On the test diet, 12 +/- 2 g/d soy protein was selected from the foods chosen. Direct comparison of test and control treatments indicated an elevated high-density lipoprotein (HDL) cholesterol concentration on the test diet (6.4% +/- 2.4%, P = .013) and a significantly reduced total to HDL cholesterol ratio (-5.9% +/- 2.3%, P = .020). The proportion of conjugated dienes in the low-density lipoprotein (LDL) cholesterol fraction was significantly reduced (8.5% +/- 3.3%, P = .020) as a marker of oxidized LDL. A combination of acceptable amounts of soy, vegetable protein, and soluble-fiber foods as part of a conventional low-fat, low-cholesterol therapeutic diet is effective in further reducing serum lipid risk factors for cardiovascular disease.

Adult↗
PubMed2000

Heat shock inhibits phosphorylation of I-kappaBalpha.

Previous studies demonstrated that induction of the heat shock response is associated with inhibition of the proinflammatory transcription factor NF-kappaB by a mechanism involving inhibition of I-kappaBalpha degradation. To provide further insight regarding the interactions of these fundamental cellular responses, the present experiments were designed to elucidate the mechanism(s) by which heat shock inhibits degradation of I-kappaBalpha. In an in vitro model of inflammatory cell signaling, treatment of RAW 264.7 murine macrophages with LPS (100 ng/mL) caused rapid degradation of I-kappaBalpha. Heat shock, 1 h before treatment with LPS, completely inhibited LPS-mediated degradation of I-kappaBalpha. Immunoprecipitation studies demonstrated that heat shock inhibited LPS-mediated ubiquitination of I-kappaBalpha. Western-blot analyses using a phosphorylated I-kappaBalpha-specific antibody demonstrated that heat shock inhibited LPS-mediated phosphorylation of I-kappaBalpha. In contrast, heat shock induced phosphorylation of c-jun. In murine fibroblasts having genetic ablation of the heat shock factor-1 gene, heat shock inhibited tumor necrosis factor-alpha mediated degradation of I-kappaBalpha. We conclude that the mechanism by which heat shock inhibits LPS-mediated degradation of I-kappaBalpha involves specific inhibition of I-kappaBalpha phosphorylation and subsequent I-kappaBalpha ubiquitination. In addition, this mechanism does not involve activation of heat shock factor-1 or the heat shock proteins regulated by heat shock factor-1.

Animals↗
PubMed2000

Hyperoxia synergistically increases TNF-alpha-induced interleukin-8 gene expression in A549 cells.

Interleukin (IL)-8 is an important mediator of acute lung injury. Hyperoxia induces IL-8 production in some cell types, but its effect on IL-8 gene expression in respiratory epithelium is not well described. In addition, IL-8 gene expression resulting from the combined effects of hyperoxia and proinflammatory cytokines has not been well characterized. We treated cultured respiratory epithelial-like cells (A549 cells) with hyperoxia alone, tumor necrosis factor (TNF)-alpha alone, or the combination of TNF-alpha and hyperoxia and evaluated IL-8 gene expression. Hyperoxia alone had a minimal effect on IL-8 gene expression, and TNF-alpha alone increased IL-8 gene expression in a time-dependent manner. In contrast, the combination of TNF-alpha and hyperoxia synergistically increased IL-8 gene expression as measured by ELISA (TNF-alpha alone for 24 h = 769 +/- 89 pg/ml vs. hyperoxia + TNF-alpha for 24 h = 1, 189 +/- 89 pg/ml) and Northern blot analyses. Experiments involving IL-8 promoter-reporter assays, electromobility shift assays, and Western blot analyses demonstrated that hyperoxia augmented TNF-alpha-mediated activation of the IL-8 promoter by a nuclear factor (NF)-kappaB-dependent mechanism and increased the duration of NF-kappaB nuclear translocation after concomitant treatment with TNF-alpha. Additional reporter gene assays demonstrated, however, that increased activation of NF-kappaB does not fully account for the synergistic effect of hyperoxia and that the NF-IL-6 site in the IL-8 promoter is also required for the synergistic effect of hyperoxia. We conclude that hyperoxia alone has a minimal effect on IL-8 gene expression but synergistically increases IL-8 gene expression in the presence of TNF-alpha by a mechanism involving cooperative interaction between the transcription factors NF-kappaB and NF-IL-6.

Binding Sites↗
PubMed2000

Cost-effectiveness analysis of reacquiring and using adenovirus types 4 and 7 vaccines in naval recruits.

Adenovirus vaccines have controlled acute respiratory disease (ARD) in military recruits since 1971. Vaccine production, however, ceased and new facilities are required. We assessed whether reacquiring and using vaccines in naval recruits is cost-effective. Three policy options were evaluated: no vaccination, seasonal vaccination, and year-round vaccination. Morbidity (outpatient and inpatient), illness costs (medical and lost training), and vaccine program costs (start-up, acquisition, and distribution) were modeled using a decision-analytic method. Results were based on a cohort of 49,079 annual trainees, a winter vaccine-preventable ARD rate of 2.6 cases per 100 person-weeks, a summer incidence rate at 10% of the winter rate, a hospitalization rate of 7.6%, and a production facility costing US$12 million. Compared to no vaccination, seasonal vaccination prevented 4,015 cases and saved $2.8 million per year. Year-round vaccination prevented 4,555 cases and saved $2.6 million. Reacquiring and using adenovirus vaccines seasonally or year-round saves money and averts suffering.

Adenovirus Infections, Human↗